1. Field
A compressor is disclosed herein.
2. Background
In general, a compressor is applicable to a vapor compression type refrigeration cycle (hereinafter, referred to as a “refrigeration cycle”), such as a refrigerator, or air conditioner, for example. A compressor can typically be divided into a hermetic type compressor, in which an electric motor drive, that is, a typical electromotor, and a compression unit or device operated by the electric motor drive are provided together at an inner space of a sealed casing, and an open type compressor, in which an electric motor drive is provided outside of the casing. The hermetic compressor is generally used for household or commercial refrigeration devices.
Compressors can further be divided into a reciprocating type, a rotary type, or a scroll type, according to a type of compressing method of a refrigerant. The reciprocating type compressor is a type that compresses a refrigerant while a piston drive linearly moves a piston. The rotary type compressor is a type that compresses a refrigerant using a rolling piston to perform an eccentric rotational movement in a compression space of the cylinder and a vane in contact with the rolling piston to partition the compression space of the cylinder into a suction chamber and a discharge chamber.
The scroll type compressor is a compressor in which a fixed scroll is fixed to an inner space of a hermetic container, and two pairs of compression chambers including a suction chamber, an intermediate pressure chamber, and a discharge chamber are consecutively formed between a fixed wrap of the fixed scroll and an orbiting wrap of a orbiting wrap while the orbiting scroll engaged with the fixed scroll performs an orbiting movement. The scroll compressor is widely used in air conditioners to compress a refrigerant due to an advantage of obtaining a relatively high compression ratio compared to the other types of compressors, as well as obtaining a stable torque as suction, compression, and discharge strokes are smoothly carried out.
Such a compressor can be divided into an upper compression type and a lower compression type according to a location of the electric motor drive and compression device. The upper compression type is a type in which the compression device is located at an upper side above the electric motor drive, and the lower compression type is a type in which the compression device is located at a lower side lower than the electric motor drive. In particular, in a case of the lower compression type, refrigerant discharged into an internal space of the casing moves to a discharge pipe located at an upper portion thereof, while oil is recovered to an oil storage space, and thus, there is a concern that oil may be mixed with the refrigerant to be discharged out of the compressor, or pushed by a pressure of the refrigerant to be stagnant at an upper side of the electric motor drive during the process. According to the present disclosure, a technique in which a passage to recover oil and a passage to discharge refrigerant are divided within the casing to reduce oil spill will be described using a high-pressure, lower compression type scroll compressor (hereinafter, referred to as a lower compression type scroll compressor) as an example.
FIG. 1 is a cross-sectional view illustrating an example of a lower compression type scroll compressor according to the related art. As illustrated in FIG. 1, a lower compression type scroll compressor according to the related art may include an electric motor drive 2 provided in an internal space of a casing 1 and having a stator and a rotor, a compression unit or device 3 provided at a lower side of the electric motor drive 2, and a rotational shaft 5 that transmits a rotational force of the electric motor drive 2 to the compression device 3. A refrigerant discharge pipe 16 may be provided at an upper portion of the casing 1. A passage (Pm) to guide oil separated from refrigerant to be recovered to an oil storage space (V3) in the electric motor drive 2, while at a same time guiding refrigerant discharged from the compression device 3 to move in a direction of the refrigerant discharge pipe 16, is formed on an inner circumferential surface of the casing 1 and an outer circumferential surface of the electric motor drive 2 or an inner portion of the electric motor drive 2.
According to the foregoing lower compression type scroll compressor according to the related art, refrigerant and oil discharged from the compression device 3 may move to an upper side of the electric motor drive 2 through the passage (Pm) provided in the electric motor drive 2, and then, may be discharged outside of the compressor through the refrigerant discharge pipe 16. At this time, oil separated from refrigerant between the electric motor drive 2 and the compression device 3 moves to the oil storage space (V3) through a passage (Pc) provided in the compression device 3, while oil separated from refrigerant at an upper side of the electric motor drive 2 moves to the oil storage space (V3) at a lower side of the compressor device 3 through the passage (Pm) provided in the electric motor drive 2 and the passage (Pc) provided in the compression device 3.
However, according to the foregoing lower compression type scroll compressor according to the related art, as both refrigerant and oil move through the passage (Pm) provided in the electric motor drive 2, oil being moved from an upper side of the electric motor drive 2 to a lower side thereof is mixed with refrigerant discharged from the compression device 3 to be discharged out of the compressor along with the refrigerant, or is not allowed to pass through the passage (Pm) of the electric motor drive 2 due to high-pressure refrigerant stagnant at an upper space of the electric motor drive 2. Then, there is a problem in that an amount of oil supplied to the compression device 3 is reduced while an amount of oil recovered to the oil storage space (V3) is rapidly reduced, thereby causing friction loss or abrasion of the compression device 3.
In addition, there is also a problem in that oil supplied to the compression device 3 through an oil passage of the rotational shaft 5 to lubricate the compression device 3, and then, flowing into a space between the electric motor drive 2 and compression device 3 is mixed with refrigerant discharged from the compression device 3 to be discharged out of the compressor while being moved to an upper side of the electric motor drive 2 along with the refrigerant, thereby further aggravating oil shortage.